Strap connection



April 12, 1949. B, Q RQEHRL 2,466,742

STRAP CONNECTION' Filed Oct. 16, 1946 UULUo-o 0 0.0 dll;

. INVENiTQOR.

BY C

Patented Apr. 12, 1949 STRAP CONNECTION Bruno C. Roehrl, Erie, Pa., assignor to National Organ Supply Company, Erie, Pa., a corporation of Pennsylvania Application October 16, 1946, Serial No. 703,537

4 Claims. 1

This invention is intended to provide an adjustable ilexible plastic strap having a unitary buckle loop and tongue. Among the features which increase the holding power of the buckle are an abrupt shoulder in the tongue and snap fasteners holding overlapping parts of the strap and buckle together. Among the features which facilitate molding and improve the quality are the use of vented inserts for forming the heads of the snap Ifasteners and the use of undercuts in ejecting members for forming overlapping portions of the strap such as the end of the tongue which overlaps the buckle loop and the keeper for the free end of the strap. The strap is adapted to molding from flexible plastics of the class known as elastomers of which polyethylene and nylon are examples. Further objects and advantages appear in the specification and claims.

In the drawings, Fig. l is a side elevation showing a strap applied to a wrist watch; Fig. 2 is an enlarged elevation partly in section through the buckle; Fig. 3 is an exploded plan view of the ends of the strap; Fig. 4 is an exploded edge view of the ends of the strap; Fig. 5 is a section through the mold forming one of the integral snap fasteners; Fig. 6 is a section through the mold forming the keeper and the buckle loop and tongue; and Figs. 7 and 8 are sections on lines I-'I and 8-8 of Fig. 6.

Referring to the drawings, i indicates a Wrist watch having spaced ears 2 for hinge pins 3 extending through enlarged ends 4 of a strap 57 5a molded of a flexible plastic such as polyethylene. Integral with the part 5 is a buckle loop 6 and a tongue 'I having its free end 8 overlappng the outer end 9 of the buckle loop. The part 5a extends through the buckle loop and overlaps the outer surface of the part 5. In the part 5 is a series of tongue receiving holes II). In the adjusted position, an offset II in the tongue extends through the selected hole I6. The offset provides an abrupt retaining shoulder resisting a separating pull. The offset is an important feature, A smooth curve such as used in the conventional tongue has substantially n0 resistance to a separating pull. This is due to the fact that both the buckle loop and tongue are of exible material.

In order to still further increase the holding power, the under side of the end 9 of the buckle loop is provided with an integral snap fastening projection having a stem o1' body I2 which extends through one of the tongue receiving holes III and an enlarged head I3 which snaps through the hole and holds the end of the buckle loop f tight against the outer surface of the strap part 5a. This in effect increases the stiifness of the buckle loop so that upon a separating pull the outer end 3 of the tongue encounters a greater resistance. On the under side of the extreme end of the strap part 5a is a similar snap fastening projection I 2a, I 3a which is received in one of a series of openings I4 in the strap part 5. The spacing of the openings IU and I4 is such that in each position of the tongue the snap fasteners register with one of the openings. So long as the snap fastening projections engage the respective openings the overlapping parts of the strap are held together so that there are no free ends projecting from the outer surface of the strap.

In case the snap fastening projection Iza, I3a becomes disengaged, the outer end of the strap part 5a is partially held in place by a loop or keeper I5 molded integral with the strap part 5. Although the snap fastening projections I2, I3 and I2a, i3d increase the resistance to a separating pull, it should be understood that these may be omitted. The abrupt retaining shoulder provided by the offset I I in the tongue provides sufcient holding power for the normal use of the strap. In fact, the holding power is sufficient even if the outer end 9 of the buckle loop is displaced above the outer end 8 of the tongue.

The strap parts 5 and 5a are each molded in one piece in a mold cavity, the novel features of which are shown in Figs. 5 to 8. Fig. 5 is a section through the part of the mold cavity forming the snap fastening projection I2a, |305. The mold comprises mold parts I6 and I1 dening a cavity I8 forming the body of the strap, In the mold part I6 is a cavity I9 forming the stem I2a of the snap fastening projection. At the outer end of the cavity I9 is an insert 20 having a cavity 2| forming the head I3a. This construction permits the forming of an abrupt shoulder 22 Which increases the holding power of the head I3a. Because of the difculty of completely filling the cavity ZI, the insert 2!) does not have an airtight t in the mold part I 6. The t of the insert is tight enough so that substantially no plastic flows beyond the cavity 2I but any air trapped in the cavity '2l is vented around the sides of the insert 26. This results in a complete filling of the cavity 2I and insures uniform holding power of the snap fastening projection.

Figs. 6, 7 and 8 show essential features of the mold for producing the strap part 5a. The mold comprises separable mold parts 23 and 24 defining a mold cavity producing the body of the strap part 5, the integral buckle loop B and part of the integral tongue '1.

In the mold part 24 are ejector pins 25 and 26 which respectively form the offset ll and end 8 of the tongue and the integral loop or keeper I5. The offset Il and end B of the tongue are formed by a passage 21 and a laterally extending recess 28 inthe ejector pin 25. The central portion of the keeper 151s formed :by a slot ,-29 in the ejector pin 20. This construction conveniently permits the molding of overlying sections` When the mold is opened the ejector pins move the strap clear of the mold part 24 into a-position in which it can be readily removed from the pins by a sidewise pull. This yin Aeiect provides for the molding of overlying sections in a mold which has no additional parts.

What I claim as new is:

1. In a strap having overlapping ends, an integral buckle loop and tongue oi flexible plastic on one of the ends, the other end extending ,through the .loop and having a series Aof tongue receiving holes, and an inwardly extending snap fastening projection on the buckle loop receivable in one of said holes.

'2. In a strap having overlapping ends, an integralbuckle loop and tongueoil fiexibleplastic on .one of the ends, the other end extending throughthe loop and having a series of vtongue receiving holes, said tongue having an .oiset extending through one of the holes and vproviding an abrupt retaining shoulder, and an inwardly extending ,snap fastening projection on the buckle loop receivable in one of said holes.

3. Ina strap of l"flexible plastic having adjust- 4 able overlapping ends, one having an integral loop through which the other extends with it free end overlapping the outer part of said en end, a series of holes in the respective ends, and

inwardly extending snap fastening projections on the outer part of the loop and on said free end receivable in said holes.

1. In a straphaving overlappingends, one end ici the strap having an integral buckle loop and tongue of flexible plastic, the other end of the -strap extending through the loop and having tongue receiving holes, and the tongue having its free -end overlapping the loop and having an yabrupt oiset adjacent the loop extending through one of the tongue receiving holes and providing Aan abrupt retaining shoulder.

BRUNO C. ROEHRL.

REFERENCES CITED The following references are of record vin the le of this patent:

UNITED STATES PATENTS 'Number Name Date 207,478 Beamer Aug. 27, 1878 786,433 Foster Apr. 4, 1905 846,476 Hynard et al Mar. 12, 1907 1,658,053 Kollstede Feb. 7,1928 1,709,181 Matlock Apr. 16, 1929 1,733,538 Herschede Oct. 29, '1929 1,778,313 Darling Oct. 14, 1930 1,851,733 Shapiro Mar. 29, 1932 2,403,780 Barbieri July 9, 1946 

